Calico cats comprise a garden of cat colors, either vibrant orange (technically known as "red"), white and black, or more subdued flaxen, blue-gray, and white. In feline genetics, the latter is known as "dilute calico." The various patterns of the calico patches are almost as ubiquitous as snowflakes. You'll never see two exactly alike.
Calicoes are almost all female, and the rare male is always sterile. (So much for the hopes of those thinking of breeding a rare line of cats.)
Learn more about this most striking color pattern, the calico cat.